Sprintf function Problem in TM4C1294

GIRISH HARI

Sprintf() is not working with TM4C1294. Please help!!! Here Is my code:

#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include "inc/hw_memmap.h"
#include "driverlib/debug.h"
#include "driverlib/gpio.h"
#include "driverlib/rom.h"
#include "driverlib/rom_map.h"
#include "driverlib/interrupt.h"
#include "driverlib/sysctl.h"
#include "driverlib/fpu.h"

void function(void)

{

char String[10];
float Float=123456.789;

FPULazyStackingEnable();
ROM_FPUEnable();

sprintf(String,"%.2f",Float);

}

clock and other peripherals are initialised. But if I try to debug this , the watchdog resets the controller, which means the controller hangs. How do I solve this problem?

Regards,

Girish.

over 7 years ago

George Mock over 7 years ago

TI__Guru**** 232790 points

The sprintf function requires lots of stack and heap. Make sure you have enough. Use the linker options --stack_size=number and --heap_size=number to set the amount of memory reserved for each.

Thanks and regards,

-George

GIRISH HARI over 7 years ago in reply to George Mock

Intellectual 805 points

George,
I have allocated 1024 bytes to stack and 256 bytes to heap.. will this be enough?

Archaeologist over 7 years ago in reply to GIRISH HARI

TI__Guru* 84225 points

Probably not. You'll probably need at least 512 bytes of heap, unless you use setvbuf. However, you should start by giving them lots of space (say, 4k each) to make sure that you can get something printing before trying to optimize the size.
processors.wiki.ti.com/.../Tips_for_using_printf

GIRISH HARI over 7 years ago in reply to Archaeologist

Intellectual 805 points

Archeologist,
I did recheck, and indeed these are my stack settings.. Things have not improved. I went through your attachment. I had already went through this earlier. it did not help!!!

Girish.

Archaeologist over 7 years ago in reply to GIRISH HARI

TI__Guru* 84225 points

Okay, I recommend that you disable the watchdog at the start of main, and comment out the calls to FPULazyStackingEnable and
ROM_FPUEnable, so that the only thing the program does is call sprintf. Does this call to sprintf now work properly?

GIRISH HARI over 7 years ago in reply to Archaeologist

Intellectual 805 points

Archeologist,
sorry Friend.. It did not work...

Girish.

George Mock over 7 years ago in reply to GIRISH HARI

TI__Guru**** 232790 points

How much stack and heap are you specifying? Try making them unreasonably large. Say 0x4000 each. Does it work then?

Thanks and regards,

-George

GIRISH HARI over 7 years ago in reply to George Mock

Intellectual 805 points

George,

Here are my stack settings:

Girish.

George Mock over 7 years ago in reply to GIRISH HARI

TI__Guru**** 232790 points

Set both stack and heap to 4096. Does it work then? The idea is to intentionally set these to unreasonably large values, so you can be certain that running out of stack or heap is not the cause of your problem.

Thanks and regards,

-George

GIRISH HARI over 7 years ago in reply to George Mock

Intellectual 805 points

George,

Sorry... did Not again work..

Girish.

Archaeologist over 7 years ago in reply to GIRISH HARI

TI__Guru* 84225 points

This is perhaps a dumb question, but how do you know it is not working? Are you stopping at the point of the sprintf call in the debugger? What happens when it does not work? Do you get a watchdog interrupt? Does it print garbage to the buffer? Does it leave the buffer unchanged? What are the symptoms?

George Mock over 7 years ago

TI__Guru**** 232790 points

The usual problems in this case have all been ruled out. You #include <stdio.h>, and you know you have enough stack and heap.

The implementation of sprintf has not changed in a long time. It is well tested. Anything is possible, but it is very unlikely the problem is in the implementation of sprintf.

The main point is, from this point on, I am just guessing at the source of the problem. And probably guessing wrong.

You could try increasing the size of the String array ...

GIRISH HARI said:
char String[10];

Try making it 20. 10 characters is exactly enough for this case. So I don't think this change will help. But it easy to try.

Otherwise, you need to step through the code and try to catch where it goes wrong. That isn't easy, because you don't know the implementation of sprintf. But I am out of other suggestions.

Thanks and regards,

-George

GIRISH HARI over 7 years ago in reply to Archaeologist

Intellectual 805 points

as per the very first question , "Does Not Work" .means " But if I try to debug this , the watchdog resets the controller, which means the controller hangs. "

GIRISH HARI over 7 years ago in reply to George Mock

Intellectual 805 points

No.. This also does not work...
Girish.

George Mock over 7 years ago in reply to GIRISH HARI

TI__Guru**** 232790 points

GIRISH HARI said:
if I try to debug this , the watchdog resets the controller

What happens if you disable the watchdog?

Thanks and regards,

-George

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Sprintf function Problem in TM4C1294